The present invention is related to a method and apparatus for making tubular composite articles, such as an acoustic liner for an aircraft nacelle.
An acoustic inlet barrel for a nacelle inlet may comprise a number of layers, including a perforated inner skin, an acoustic core, and an impervious outer skin. Typically, the inner skin is formed from sectors that are bolted together at axially extending seams. Ideally, however, the perforated skin has no internal seams or other features which may degrade the acoustic performance of the barrel.
U.S. Published Patent Application No. 2004/0065775 discloses a tool for molding an air intake, and more specifically for forming a one-piece inner skin having no internal seams. The tool comprises a mandrel having four arcuate sectors, a fixed sector that does not move during normal operation to the tool, two movable articulated sectors each hingedly connected to either side of the first sector; and a movable key sector which is independent from the other sectors and insertable between the articulated sectors. By virtue of the hinges, the articulated sectors remain connected to the fixed sector and cannot be separated therefrom. Locks are provided to secure the key sector to the articulated sectors. When in the molding position, the four sectors together define, by their external surfaces, a continuous surface corresponding to the internal surface of an air intake. A control device, disconnectable from the mandrel, may be used to adjust the movable sectors between a molding position and an non-molding position.